1. Field of the Invention
The present invention relates to lamp sockets for automobile headlights.
2. Description of the Related Art
Recently developed lamps, such as automobile headlights, are as bright as daylight. Such a lamp has a lamp-side plugging section which is plugged into the socket-side plugging section provided in the socket body of a socket. The socket-side plugging section has a pair of terminals for contact with the lamp terminal and the contact portion of the lamp-side plugging section, respectively. The socket body has an engaging portion for engagement with an engaging pin provided at the lamp-side plugging section when the lamp- and socket-side plugging sections are coupled.
The lamp terminal and the contact portion are brought into contact with the terminals of the socket by plugging the lamp-side plugging section into the socket-side plugging section such that the engaging pin of the lamp-side plugging section engages the engaging portion of the socket.
However, the engaging pin has a difficulty in sliding on the engaging portion, making it difficult to attach or detach the lamp from the socket. Where the thickness of the engaging pin is reduced with respect to the engaging portion to make the attachment or detachment easy, it is frequent that the engaging pin comes out of the engaging portion.
Accordingly, it is an object of the invention to provide a lamp socket allowing smooth movement of the engaging pin, making it easy to attach or detach a lamp body from the socket body.
According to the invention there is provided a lamp socket comprising a socket body having a cylindrical section with a plugging cavity into which a plugging section of a lamp is plugged; a first-type terminal provided at a central area of the plugging cavity for contact with a lamp terminal; a second-type terminal provided at a periphery of the plugging cavity for contact with a peripheral contact provided on the plugging section of the lamp; and a lamp retention section having an insertion groove extending from an edge of the cylindrical section in an axial direction of the cylindrical section for receiving an engaging pin provided on a side wall of a the plugging section and an engaging portion extending from the insertion groove in a circumferential direction of the cylindrical section for engagement with the engaging pin; and a slit provided in the cylindrical section in parallel to the engaging portion to form a flexible portion between them for facilitating movement of the engaging pin along the engaging portion.
When the engaging pin of the lamp is inserted into the engaging portion of the socket to plug the lamp into the socket so that the lamp terminal and contact section are brought into contact with the first and second terminals of the socket, the flexible portion is flexed by the engaging pin, reducing the friction between the engaging pin and the engaging portion and facilitating attachment of the lamp to the socket.
To remove the lamp from the socket, the flexible portion is flexed to reduce the friction between the engaging pin and the engaging portion, facilitating the removal operation.
The engaging portion may be an engaging hole having a notch at its end opposite to the end communicating with the insertion groove. The notch facilitates expansion in the plugging direction of the engaging hole by the engaging pin and insertion of the engaging pin into the engaging portion.
The engaging hole may have a pair of parallel walls, at least one of which has a projection thereon. When the engaging pin is put into the engaging hole followed by rotation of the lamp or the reverse operation is made, the engaging pin passes the projection, producing a click and enhancing the lamp attaching or detaching operation.
The cylindrical section may be provided with a flange portion at its outer edge and a thickening portion extending from the flange portion to thicken a bottom wall of the insertion groove. The flange and thickening portions keep the strength of the cylindrical section despite the presence of the insertion groove and the engaging hole. As a result, the cylindrical section of the lamp is able to withstand against a forcible attempt to plug the lamp to the socket in a wrong alignment.
The slit may be provided on a side of the engaging hole opposite to the flange to form the flexible portion between them. When the engaging pin is put into the engaging hole so that the lamp terminal and the contact section are brought into contact with the first and second terminals, the flexible portion is flexed to expand the engaging hole, reducing the friction between the engaging pin and the engaging hole and facilitating attachment of the lamp to the socket. Where the lamp is removed, the flexible portion similarly is flexed to facilitate the removal operation.